Delete and re-download the resources.cfg file in the mods folder
Naturally, I searched it up to try and find a solution and I have done the majority of things people tell you to do: I haven't played the Sims 3 for a long time and I have it on Origin, anyway, I recently downloaded some package files for custom content and none of it is showing in cas and the 'nointro' package doesn't work as the intro pops up and I have to click to skip. So you can probably already tell what this is about but let me explain because every situation is different.
